Single contact distance relay system



NOV, 18, 1947 s. LgcsoLDsBoRouGl-l Er AL" 2,430,871

' SINGLE CONTACT DISTANQE RELAY SYSTMS Filed nay 5, 1944 l DE z/a zza Tz Y ATTORN EY Patented Nov. 18, 1947 SINGLE CONTACT DISTANCE RELAY SYSTEM A Shirley L. Goldsborough, Basking Ridge., and Herbert W. Lensner, East Orange, N. J., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Penn- Sylvania.

Application May 5,

18 Claims.

Our invention relates to protective relaying systems utilizing distance-responsive relays for protecting transmission lines against faults.

The principal object of our invention is to provide a reorganization of such a protective system in such manner as to make it possible to utilize a sensitive or third-zone distance-element carrying but a single contact.

A more specic object is to so correlate the timers in the plurality of protective relaying equipments for a plurality of line-sections terminating in a common bus, that the third-zone tripping-contacts of different timing relays momentarily close at diierent times, so that an extremely fast-moving third-zone distance-responsive contact does not need to be connected in this particular tripping-circuit in order to safeguard against a faulty tripping-operation, as will be subsequently described. A more speciiio object of our invention is to provide a novel timer-control whereby the timer is under control of the directional relay-element as well as the thirdzone relay-element.

A further object of our invention is to provide a carrier-current protective relaying system in which the third-zone distance-responsive contacts which are utilized to initiate the carriercurrent transmission are each connected in series with the coil of an auxiliary relay, so as to eliminate the necessity for any other contacts whatever on the sensitive third-zone distance-responsive elements. In order to make this carrierstarting control feasible, notwithstanding the additional voltage-drop which is introduced by including the coil of the auxiliary relay in the carrier-starting control-circuit, it is usually necessary, in practicing our invention, to bias the cathode of the transmitter oscillator tube to some intermediate potential between the potentials of the terminals of the source of electrical energy for the oscillator tube.

A still more specific object of our invention is to apply the oscillator-controlling circuits just mentioned to a small auxiliary oscillator which is provided as a part of an electronic keyer. This keyer, without our special single-contact thirdzone element, is described and claimed in a companion application of iHerbert W. Lensner, Serial No. 530,134, filed April 8, 1944.

Prior to our present invention, a standard distance-type relaying system has utilized a thirdzone distance-responsive element having a makecontact, an independent, bridge-type, make-contact, and a back-contact. The back-contact was needed for the purpose of aiding in the selective 1944, Serial No. 534,223

2 control of an auxiliary relay which provided additional contacts which were responsive to the third-zone distance-response. The first makecontact was required for performing a quick response or function, either associated with the starting of carrier-current transmission, or, even when there was no carrier, in connection with out-oi-step protection and for other purposes. The bridge-type make-contact was needed ior providing high-speed coordination for preventing faulty tripping in the third-zone timer tripping circuits, which have already been referred to, and which will be explained more in detail hereinafter.

The effect of the previously common, multiplecontact construction of the third-zone distanceelement has been not only to complicate the structure and render it difficult to adjust, but it has loaded upithe moving element of the relay so much that its impedance response-characteristic has been aected. These disadvantages are avoided in our new arrangements, utilizing the simplified, or single-contact, third-zone distanceelement.

With the foregoing and other objects in View, our invention consists in the systems, circuits, combinations, parts and methods, hereinafter described and claimed, and illustrated in the accompanying drawing, wherein:

Figure 1 is a single-line diagram which will be referred to in the explanation of the advantages and operation of our invention, and

Fig. 2 is a diagrammatic view of circuits and apparatus embodying our invention in a preferred form of embodiment.

Fig. 1 indicates the application of our invention to the protection of a three-phase transmission-line 3, which is indicated in Fig. 1 in singleline diagram. The transmission-line extends between a plurality of stations M, N, O, P, etc., which are represented by three-phase buses which are indicated, in Fig. 1, as single vertical lines. In general, it may be assumed that each station-bus represents a three-phase system which, in the general case, will include synchronous generators as well as load-devices. The transmisson-line 3 is sectionalized at the several stations, by being provided with circuit-breakers l to lil at the several line-terminals which are connected to the several buses M, N, O and P.

In Fig. l, a three-zone distance-responsive protective system is indicated, in connection with stations N and O, by means of stepped lines (Zl-SZZ-iZB and SZl-BZZ-EZS which are associated with the breakers 6 and t, respectively,

to indicate a iirst zone ZI in which the trippingresponse is substantially instantaneous, a second zone Z2 in which the tripping-response is obtained only after a time-delay which is symbolically indicated by a vertical step in the line, and a third zone Z3 which is associated with a still longer time-delay.

Our invention relates to the terminal relaying equipment such as would be utilized at any one of the line-terminals 4 to IU in Fig. 1. For purposes of illustration, we have shown in detail, in Fig. 2, the terminal equipment which is associated with the breaker E at the station-bus N.

The various relays which make up our protective-relaying system include various line-responsive relays, the various coils and contacts of which are separated into alternating-current circuits and direct-current circuits, respectively, the various circuits being arranged, so far as practicable, after the matter of a schematic diagram or across-the-line diagram. ln each case, the main or operating coil of the relay is given a letter-designation or legend, and the saine letter-designation or legend is applied to all or the contacts of that relay. The relays and switches are invariably shown in their open or deenergized positions. When a given relay has, in addition to its main or operating winding, an auxiliary winding, such as a restraining or polarizing coil or winding, the auxiliary winding is given the same letter-designation, with a subscript. Arrows or dotted lines are used, to symbolically indicate how the various parts of each relay are connected together. When corresponding elements are utilized in different phases, they are distinguished by suxes, such as A, B and C, for the dilerent phases.

In Fig. 2, the breaker 6 is illustrated as a threepole breaker, having its several poles associated with several line-conductors of the three-phase line 3. The breaker is illustrated as being provided with an auxiliary make-contact switch Ga, and a trip-coil TC. The protective relaying equipment for controlling the breaker (i comprises iour relaying panels II, I2, i3 and Illone for each phase, and one for ground-fault responses.

The phase-A relay-panel Il, for example, includes a directional element DA which has a current-coil DA, a voltage-coil DAV, and a makecontact DA, the latter being shown off to one side, in connection with the direct-current relaying-circuits. The phase-A panel II also includes rst, second, and third-zone distance-responsive relaying-elements having current-responsive operating-coils ZIA, ZZA and ZBA, respectively, and voltage-responsive restraintwindings which are grouped together under the designation ZAV. These distance-relays are each provided with a make-contact which is oompletely identied by using the relay-designation ZIA, ZiA, or Z3A, as the case may be. rlhe three distance-elements ZIA, Z2A and Z3A respond to line-faults at different distances from the rela-ying station. while the directional element DA responds when said faults are accompanied by a current-direction into the protected line-section at the relaying terminal.

The phase-B and phase-C panels I2 and I3 are similar to the phase-A panel, except that the change in phase is indicated by the substituticn of the letters B and C, respectively, in place of the letter A, in the various relay-designations.

The ground-fault relaying-panel I4 in Fig. 2 comprises a directional element DO, having a.

current-responsive coil DO and a Voltage-responsive coil DOv, and a single make-contact DO. This panel also includes a heavy-current overcurrent ground-fault detector IOZ, and a sensitive or light-current ground-fault detector IOS, each having a single make-contact which is designated by the appropriate relay designation IO'.

v`or IOS as the case may be.

The relaying energy for energizing the coils cf the various relays is obtained from a bank of line-current transformers I5, a bank of auxiliary current-transformers I5, a bank of potentialtransformers I'I, and a bank of auxiliary potential-transformers I8, as clearly shown in the drawing, and as is well known in the art, so that a detailed description of the connections is not believed to be necessary.

The direct-current relaying-connections oi Fig. 2 are shown in schematic form. Attention will rst be directed to the three third-zone distance-responsive contacts Z3A, Z3B and ZSC, which are shown about half way down, in the schematic diagram. These third-zone contacts are the contacts which are needed in order to perform a quick-response function, and in the particular relaying system which is shown in Fig. 2, this function consists in the starting of carriercurrent transmission by means of a carrier-current transmitter 2 I, which is a part of a carriercurrent equipment also including a carrier-current receiver 22. The carrier-current equipment is illustrated as being coupled to the third phase-conductor of the line 3, through a coupling transformer 23 and a coupling capacitor 24 in a manner which is or may be well known or conventional.

In accordance with our invention, the three third-zone contacts Z3A, Z3B and ZSC are each connected in a separate circuit, in series with the operating-coil of an associated auxiliary relay, the three auxiliary relays being designated CSA, CSB and CSC, respectively, representing contactor-switches for supplying an additional contact or contactswvhich avoid the necessity for multiplying the number of contacts which aro actually carried by the third-zone distance-elements ZSA, Z3B and ZSC. In Fig. 2, the three circuits just referred to extend from the negative bus through the various third-zone contacts. such as Z3A, 23B and ZSC, respectively, and thence through the associated coils CSA, CSB and CSC, as the case may be, to a common circuitconnection 25, which is connected to the positive relaying bus (-l-l through a resistance RI.

Attention may now be directed to the tripcircuit connections of the schematic diagram in Fig. 2. Various trip-circuit connections are Shown, starting with the phase-A directional contact DA, which is connected between the negative bus and. a relaying circuit 25. A tripping circuit continues on, from the conductor Z, through the first-zone contact ZIA, to a tripping bus Z'I, vfrom which a trip-circuit is continued, extending through the trip-coil TC and the breaker-switch 5a to the positive bus (-I-). A second trip-circuit extends from the conductor 25 through the second-zone contact Z2A to a conductor 28 and thence through a timer-contactI T2A to the tripping-bus 21. A third phase-A tripping circuit extends from the conductor through the contact CSA of the auxiliary thirdzone relay, to a conductor 2B, from which a tripping circuit is continued, through a timer-contact TBA, to the tripping bus 21.

In accordance with our invention, the conductor 29 of the third-zone tripping circuit is also utilized to energize another auxiliary switch CSAI, having a single make-contact CSAI which is utilized to energize the phase-A timer 'I--A. The timer T-A is illustrated as utilizing an alternating-current motor which is energized from a suitable alternating-current circuit, as by means of a saturating current-transformer ST. This timer T-A is provided with the second and thirdzone contacts T2A and TBA which are momentarily closed after suitable time-intervals following the initiation of the timer-operation.

The phase-B and phase-C tripping circuits, dis-- tinguished by the letter-designations B and C, are similar to the phase-A circuits already described, and no further explanation is believed to be necessary, other than to note that the relaying conductor 28 is common to all three phases, and is also connected to the tripping-bus 2'! through a contact 3| of a receiver-relay RR, said receiver-relay having an operating-coil RR and a holding-coil RRH which will be subsequently described. The common phase-circuit relayingconductor 28 is also utilized to energize the coil CSP of an auxiliary phase-Tault relay or contactor-switch CSP, which is thus energized whenever the directional element and the second-zone distance-element both respond, in any one of the three line-phases A, B or C.

Fig. 2 indicates a single ground-fault tripping-circuit which extends from the negative bus through the directional contact DO and the fault-detector contact IOZ, to a relaying conductor 32, and thence, through a contact S3 oi the receiver relay RR, to the tripping bus 2l. The conductor 32 is also utilized to energize the coil CSG of an auxiliary ground-fault relay or contactor-switch CSG.

We come, now, to the three third-zone contactsZBA, 23B and Z3C, which have already been described as being utilized to energize the conduotor 25 through the respective coils of the auxiliary relays CSA, CSB and CSC. The conductor 25 is primarily utilized to control the operation of an oscillator-tube OSC. broader aspects of our invention, any sort of tube-control may be utilized, but in the more specilic aspects of our invention, a particular kind of control is preferred. Furthermore, in

the broader aspects of our invention, the oscillater-tube OSC may be any oscillation-generator, but in accordance with the more specific aspects of our invention, it is preferred to utilize this oscillator-tube OSC as a part of socalled electronic keyer, which utilized to key or control the carrier-current transmitter 2i, which is provided with its own oscillator-tube OSC.

In the particular form of keyer-control which is shown in Fig. 2, the keyer-oscillator OSC has its plate-circuit energized from the positive bus through a series dropping-resistor which is connected to a conductor 34, and thence, through a radio-frequency choke RFC, to the anode-lead of the oscillator OSC. The conductor 3d of this plate-energizing circuit is connected to the previously mentioned control-circuit conductor through the serially connected back-contacts CSP and CSG, the mid-point of which is connected, at 35, to a circuit extending to the negative bus and including the ground-fault detector-contact 103, and preferably also a resister R3, which may be utilized for the purpose of avoiding a short-circuiting of the auxiliaryrelay coils CSA, CSB or CSC. The ground-fault In the contact IOS is utilized to by-pass the phase-fault contact CSP, in order to provide ground-preference in a well-known manner.

In a manner which is also well known, the two 5 serially connected back-contacts CSP and CSG are shunted by a circuit which includes the receiver-relay operating-coil RR and a serially connected resistance R4, thus providing a second circuit which joins the conductors 25 and 34.

The oscillator OSC is connected to a tuned circuit which includes two capacitors Cl and C2, and the primary winding of a transformer 39. The intermediate point of the two capacitors Cl and C2 is connected to the cathode-lead 4I] of the oscillator tube OSC. The junction-point between the capacitor CI and the transformer-primary 39 is connected to the grid-circuit 4l of the oscillator OSC, and this grid-circuit is connected to the cathode-circuit 4D through a grid-leak GL. The connection-point between the capacitor C2 and the transformer-primary 39 is connected, at 42, through a blocking-capacitor BC, to the anodelead 35.

In accordance with our invention, we bias the cathode-lead 4t of the keyer-oscillator OSC by connecting it to an intermediate point 43 in a potentiometer 44 that is connected across the terminals (-1-) and of the unidirectionalcurrent source which energizes the oscillator. The reason for this bias can best be understood by referring to the operation of the oscillator OSC. Normally, this oscillator is in an oscillating condition, receiving power in a plate-anode circuit which can be ztraced from the positive bus through the series dropping resistor R2, the conductor 34, the radio-frequency choke RFC, the anode-lead 35, the oscillator tube OSC', the cathode-lead 4i), and the potentiometer-connection 43, to the negative bus The eilective potential which is applied to the oscillator is the potential .ng between the points 34 and 43.

This oscillation is stopped whenever any one of the contacts ZA, Z3B, 23C or 103 is closed, the eiTect of which will be to bring the potential of the point .t4 within from zero to some 10 or 20 volts of the potential of the negative bus depending upon how many of these contacts close, and depending also upon the resistance-drop in the coils CSA, CSB or CSC, or the resistor R3 if said resistor is utilized. The potentiometer-connection 43 raises the potential of the oscillatorcathode to a point which is preferably more positive than is the point 34 upon the closure of any one of the control-contacts ZEA, Z3B, ZSC or IO3. In this manner, we are enabled to utilize the controlling-contacts ZSA, ZSB and ZSC in a control-circuit which includes the coils of the auxiliary relays CSA, CSB and CSC, respectively, without ruiming the hazard of having the oscillator OSC maintain its oscillations at a time when it is desired to cut oilU said oscillations.

potentiometer-tap potential at 43 is preferably raised tovoltage such as 75 volts, considerably higher than the resistance-drop in the auxiliary-relay coils CSA, CSB and CSC, leaving at least 4) volts. of the total source-voltage of 125 volts, for the operation of the oscillator OSC. This removes the hazard of chattering contacts Z3A, Z333, ZSC or 103, by permitting them to draw an are of an appreciable length, while still keeping the keyer-oscillator stopped.

The manner in which the keyer-oscillator OSC is utilised, to control the transmitter-oscillator OSC', aside from the use of the control-circuits 75 containing the coils CSA, CSB and CSC, and aside 7 from the use of the biasing potentiometer-connection 43, is the same as is described and claimed in the previously mentioned Lensner application.

Thus, the output of the transformer 39, in the tuned circuit of the keiler-oscillator OSC, is rectied by connecting the transformer-secondary 45 to a rectier-valve RV which is loaded through a 'esistor R5 so that, whenever the keyer-oscillator OSC is generating oscillations, a negative-drop is produced in the load-resistor R5, thus producing a unidirectional controlling-voltage which is applied to the grid oi the transmitter-Oscillator OSC' such a way as to block the oscillation of said transmitter oscillator OSC', thereby preventing the transmission or carrier-current energy. The grid-control circuit just mentioned may be traced from the negative bus through the load-resistor R55, and a radio-frequency impedance RFZ, to the grid-circuit 41 of the oscillator OSC' of the carrier-current transmitter 2|. Since the keyeroscillator OSC is normally oscillating, the gridbloclring potential normally appears across the load-resistor R5, and the oscillation-generation of the transrnitter-oscillator OSC' is thus normally blocked, so that no radio-frequency energy is normally being transmitted onto the protected line-section by the carrier-current transmitter 2 l.

The equipment is completed by means of a receiver-relay holding-coil RRH which is energized in the plate circuit of the receiver-tube REC of the carrier-current receiver 22.

In operation, when any fault occurs upon the transmission system, within the reach of any one of the three sensitive phase-fault distance-responsive relays ZSA, 23B or ZSC, or Within the balance-point of the sensitive ground-fault relay E03, the potential of the anode-circuit conductor 3s of the lreyer-oscillator OSC is brought to a potential which is substantially as negative as, and preferably, to be on the safe side, more negative than. the potential of the potentiometer-point 43 which is connected to the cathode-lead 40 of said keyer-oscillator. This eiectually blocks the operation of the keyer-oscillator, and reduces, substantially to zero, the voltage-drop across the load-resistor R5, thus removing the blocking-potential from the transmitter-Oscillator OSC' and causing the latter to immediately begin oscillating.

1f the line-fault is accompanied by a linecurrent iiowing in the internal direction, or in the direction into the protected line-section 3 at the relaying terminal, one or more of the directional elements DA, DB, DC or DO will operate, and if the corresponding second-zone element ZZA, ZZB, ZEC or 102 also picks up, then the auxiliary phase-fault or ground-fault relay CSP or CSG will also pick up, opening its back-contact between the conductors 25 and 34, thereby restoring the potential of the point 34 to a Value depending upon the relative impedances of the resistances R2 and R4 and the other constants of the circuit, so that the point B is suciently positive with respect to the potentiometer-point a3 so that the keyer-oscillater OSC begins to oscillate again, thereby restoring ne biasing potential which is developed across the load-resistor R5, and thus again blocking the oscillation of the transmitter oscillator OSC.

It will thus be observed that we utilize the heifer-oscillator OSC by rectifying its oscillatorycurrent output, by means of a rectifier valve RV which energzes the load-resistor R5 and produces a unidirectional controlling-voltage therein. The ripples of this controlling-voltage can be removed, more or less completely, by suitable means which are symbolically indicated by means of a filter-capacitor FC which is connected across the terminals of the load-resistor R5. Ir' this filtering action is suiciently complete, the frequency of the oscillations of the keyer-oscillator OSC is immaterial. We prefer, however, to utilize a keyer-oscillator frequency which is higher than the frequency of the carrier-current which is produced by the carrier-current transmitter 2l`, utilizing a, keyer frequency which may be of the order of two or three times the transmitter-irequency. Thus the ripples which appear in the voltage-drop across the load-resistor R5 are of a higher frequency than the carrier-current frequency, so that the ripple in the rectiiied output of the rectifier-valve RV will not modulate the carrier-current energy which is generated by the carrier-current transmitter 2|.

In the operation of the tripping circuits as shown in Fig. 2, our present invention is particularly concerned with the operation of the third-Zone phase-fault tripping-circuits which include the timer-contacts TBA, TBB and TSC, respectively. Previous to our present invention, it had been customary to initiate the operation of the several timers T-A, T-B and T-C in response t0 the corresponding third-zone distance-element ZSA, ZSB or ZSC, or thro-ugh auxiliary relays similar to our relays CSA, CSB and CSC, but diierently controlled so that the auxiliary-relay coils were not in series with the distance-element contacts, in the carrier-starting circuits or other circuits requiring a quick response to an operation ci any one of the three phase-fault third-zone elements 23A, ZSB and Z3C. In the previous third-Zone tripping circuits, it was also customary to utilize timingrelays having the same time-settings, in the lineterminals which are connected to the stationbus, such as in the line-terminals 5 and 6 of Fig. l, and it was also customary, and necessary to utilize quick-acting contacts which were actually carried by the third-Zone distance-elements, rather than tolerating the slight timehesitation inherent in utilizing the contacts of auxiliary relays, however fast, such as our auxiliary relays CSA, CSB and CSC.

The reason for this prior-art practice will best be understood by reference to Fig. l, wherein the relay-operation at the points 5 and 6 at the station N will be considered, for the case of a fault at the location X near the far end of the linesection O-P, assuming load-current normally flowing from the station N to tne station M, as indicated by the arrow. With a ault locate at the point X, as shown, the fault should normally be cleared by the breaker at 8, but if, for any reason, the fault is not cleared by the breaker 8, the duty will revolve upon the relays at the point N to clear the fault through the thirdzone tripping circuit. Reference to Fig. 2 will show that the tripping circuit includes (assuming a phase-A fault) the directionalcontact DA, the auxiliary third-zone Contact CSA, and the timer-contact TSA. Previous to our invention, a Z3A contact was utilized in place of the CSA contact.

By reason of the presence oi the directional contacts DA, it follows that the breaker 5 of Fig. l vill operate under these condA ns, but the breaker 5 will not, because while the distanceelements associated with the breaker 5 will reach out to substantially the same distances as those of the breaker 6, the fault-current direction for the breaker will be in the wrong direction t0 energize the directional elements which are associated with that breaker. However, immediately upon the clearing of the fault by the thirdzone timer-action of the breaker 6, the currentdirection in the breaker 5 will immediately reverse, because a load-condition is assumed in which the load-current is ovving from N to M, as shown by the arrow, and hence if, at that moment, the Z3A Contact and the T3A Contact of the breaker-5 relays were closed, a faulty tripping-operation would be obtained at the breaker 5. It was for this reason that a fastacting contact, actually carried by the thirdzone element itself, was required in the tripping circuit, in the place where We utilize our CSA contact, so that this contact would open faster than the directional contact DA could close, at the moment of clearing the fault at the breaker E, so that a faulty operation of the breaker 5 would not be obtained.

In accordance with our present invention, We avoid the necessity for very quickly reopening the 23A contact which was previously utilized in the third-zone tripping-circuit, by making the timers of the relaying equipments associated with the breakers 5 and 6, in the illustrated case, momentarily close their third-zone contacts at slightly different times, so that, at the moment when the breaker 6 opened, on its third-zone timer-contact T3A, the corresponding timer-contact of the breaker 5 would either not yet have been made, or would have been made and broken as the timer-relay moved on past the setting of its contact-member TSA. In this manner, we do not need to have the quick-acting ZSA contact in the tripping circuit, but We may utilize a contact carried by an auxiliary relay CSA, which only needs to be fast enough to reopen before the timer-contact TSA makes contact again on its resetting stroke.

In the particular illustrated embodiment of our invention shown in Fig. 2, we have gone a step further than merely unequalizing the timer- .1.,

settings at any particular station, and We have made the initiation of the timer-operation dependent upon current-direction as Well as upon a third-zone distance-response. We have accomplished this result by utilizing the auxiliary relays CSAl', CSB! and CSCI, the operatingcoils of which are energized from the several circuits '29, such as the phase-A circuit which is in series with the directional contact DA as well as the auxiliary third-zone contact CSA. In this manner, in the illustrated case assumed in connection with Fig. 1, the timer T-A for the breaker 5 will not operate at all, being prevented from doing s0 by the DA contact, as long as any fault-current continued, and being prevented from operating by the dropping out of the distance-responsive element as soon as the fault was cleared by the opening of the breaker 6.

Other features of the illustrated form of embodiment of our invention, which have not been particularly discussed, are more or less conventional in the art, as shown in such patents as the Harder et al. Patent 2,144,493, and our Patent 2,255,934; and it is believed that such features will be readily understood without further detailed explanation.

While we have shown our invention in a single preferred form of embodiment, we Wish it to be understood that such illustration is only illusl0 trative, as the general features of our invention are susceptible of being incorporated in widely different structures and organizations. We desire, therefore, that the appended claims shall be accorded the broadest construction consistent with their language.

We claim as our invention:

l. A plurality of protective relaying equipments for respectively controlling plurality of line-sectionalizing circuit-interrupting means in a plurality of line-sections terminating in a common bus at a relaying station, each equipment comprising nrst, second, and third-zone distanceresponsive relaying-means for responding to lineiaults diierent distances from the relaying station, at least some of said relaying-means being selectively responsive when said faults are accompanied by a current-direction into the protected line-section at the relaying terminal, an auxiliary relay, means for utilizing a contact of the third-zone relay for performing a quickresponse function, means for utilizing the same Contact of the third-zone relay for controlling the energization of the auxiliary relay, a timing relay, means for utilizing the auxiliary relay in controlling the initiation of the timingrelay operation, means for utilizing the operations or said rst and second-zone relays and said quick-response function in a plurality of control circuits for causing line-sectionalizing circuit-interrupter operations, and means for utilizing a timing-relay operation in causing a linesectionalizing circuit-interrupter operation, the several relaying equipments at said station being so correlated that the aforesaid line-sectionalizing operations of diierent timing relays occur at different times.

2. A plurality of protective relaying equipments for respectively controlling a plurality of linesectionalizing circuit-interrupting means in a plurality of line-sections terminating in a common bus at a relaying station, each equipment comprising first, second, and third-zone distanceresponsive relaying-means for responding to linefaults at different distances from the relaying station, directionally responsive relaying-means for responding when said faults are accompanied by a current-direction into the protected linesection at the relaying terminal, an auxiliary relay, means for utilizing a contact of the thirdzone relay for performing a quick-response function, means for utilizing the same contact of the third-zone relay for controlling the energization of the auxiliary relay, a timing relay, means for utilizing the auxiliary relay in controlling the Initiation of the timing-relay operation, means for utilizing the operations of said directional relay and said first and second-zone relays and said quick-response function in a plurality of control circuits for causing line-sectionalizing circuitinterrupter operations, and means for utilizing a timing-relay operation in causing a line-sectionalizing circuit-interrupter operation, the several relaying equipments at said station being so correlated that the aforesaid line-sectionalizing operations of different timing relays occur at different f times.

3. A plurality of protective relaying equipments for respectively controlling a plurality of linesectionalizing circuit-interrupting means in a plurality of line-sections terminating in a common bus at a relaying station, each equipment comprising rst, second, and third-zone distanceresponsive relaying-means for responding to linefaults at different distances from the relaying i li station, at least some of said relaying-meansbeing selectively responsive when said faults are accompanied by a current-direction into the protected line-section at the relaying terminal, an auxiliary relay, means for utilizing a contact of the third-zone relay for performing a quick-response function, means for utilizing the same contact of the third-zone relay for controlling the energization of the auxiliary relay, a timing relay, means for utilizing the auxiliary relay in controlling the initiation of the timing-relay operation, means for utilizing .the operations of said first and second-zone relays and said quick-response function in a plurality of control-circuits for causing line-sectionalizing circuit-interrupter operations, and circuit-interrupter control-circuit means, serially including contacts of said auxiliary relay, and said timing relay, for causing a line-sectionalizing circuit-interrupter operation, tne several relaying equipments at said station being so correlated that the aforesaid linesectionalizing contacts of different timing relays momentarily close at different times.

4. A plurality of protective relaying equipments for respectively controlling a plurality of line-sectionalizing circuit-interrupting means in a plurality of line-sections terminating in a common bus at a relaying station, each equipment comprising rst, second, and third-zone distanceresponsive relaying-means for responding to linefaults at different distances from the relaying station, directionally responsive relaying-means for responding when said faults are accompanied by a current-direction into the protected linesection at the relaying terminal, an auxiliary relay, means for utilizing a contact of the thirdzone relay for performing a quick-response function, means for utilizing the same contact of the third-zone relay for controlling the energization of the auxiliary relay, a timing relay, means for utilizing the auxiliary relay in controlling the initiation of the timing-relay operation, means for utilizing the operations of said directional relay and said first, and second-zone relays and said quick-response function in a plurality of controlcircuits for causing line-sectionalizing circuitinterruptor operations, and circuit-interrupter control-circuit means, serially including contacts of said directional relay, said auxiliary relay, and said timing relay, for causing a linesectionalizing circuit-interrupter operation, the several relaying equipments at said station being so correlated that the aforesaid line-sectionalizing contacts of different timing relays momentarily close at different times.

5. Protective relaying equipment for controlling a line-sectionalizing circuit -interrupting means at a terminal of a line-section to be protected, comprising rst, second, and third-zone distance-responsive relaying-means for responding to line-faults at different distances from the relaying terminal, directionally responsive relaying-means for responding when said faults are accompanied by a current-direction into the protected line-section at the relaying terminal, an auxiliary relay, means for utilizing a contact of the third-zone relay for performing a quick-response function, means for utilizing the same contact of the third-zone relay for controlling the energization of the auxiliary relay, a timing relay, means for causing said timing relay to be energized in response to both said directional relay and said auxiliary relay, means for utilizing the operations of said directional relay and said first and second-zone relays and said quick-response function in a plurality of control-circuits for causing line-sectionalizing circuit-interrupter operations, and circuit-interruptor control-circuit means, serially. including contacts of said directional relay, said auxiliary relay, and said timing relay, for causing a line-sectionalizing circuit interrupter operation.

6. Protective relaying equipment for controlling a line-sectionalizing circuit-interrupting means at a terminal of a line-section to be protected, comprising rst, second, and third-zone distance-responsive relaying-means for responding t0 line-faults at different distances from the relaying terminal, at least some of said relayingmeans directionally responding when said faults are accompanied by a current-direction into the protected line-section at the relaying terminal,

an auxiliary relay, an oscillator-tube, means for utilizing a contact of the third-zone relay for quickly controlling the oscillator-tube with respect to its oscillation-generation, means for utilizing the same contact of the third-zone relay for controlling the energization of the auxiliary relay, means for utilizing the operations of said rst and second-zone relays and said oscillatortube in a plurality of control circuits for causing line-sectionalizing circuit-interrupter operations, and circuit-interrupter control-circuit means for utilizing contacts of said auxiliary relay fer causing a line-sectionalizing circuit-interrupter operation.

'7. Protective relaying equipment for controlling a line-sectionalizing circuit-interrupting means at a terminal of a line-section to be protected, comprising first, second, and third-zone distance-responsive relaying-means for responding to line-faults at different distances from the relaying terminal, directionally responsive relaying-means for responding when said faults are accompanied by a current-direction into the protected line-section at the relaying terminal, an auxiliary relay, an oscillator-tube, means for utilizing a Contact of the third-zone relay for quickly controlling the oscillator-tube with respect to its oscillation-generation, means for utilizing the same contact of the third-zone relay for ccntrolling the energizaton of the auxiliary relay, means for utilizing the operations of said directional relay, said rst and second-zone relays, and said oscillator-tube, in a plurality of control circuits for causing line-sectionalizing circuit-interruptor operations, and circuit-interrupter control-circuit means for utilizing contacts of said directional relay and said auxiliary relay in series with each other for causing a line-sectionalizing circuit-interruptor operation.

8. Protective relaying equipment for controlling a line-sectionalizing circuit-interrupting means at a terminal of a line-section to be protected, comprising first, second, and third-zone distance-responsive relaying-means for respondving to line-faults at different distances from the relaying terminal, at least some of said relayingmeans directionally responding when said faults are accompanied by a current-direction into the protected line-section at the relaying terminal, an auxiliary relay, an electronic tube, means for utilizing a Contact of the third-zone relay and the coil of the auxiliary relay in series with each other for together effecting a control over the condition of operation or nonoperation of the electronic tube, and means for utilizing the operations of said first and second-zone relays, said auxiliary relay and said electronic tube in the control of a plurality of control-circuits for caus- 13 ing line-seotionalizing circuit-interrupter operations.

9. Protective relaying equipment for controlling a line-sectionalizing circuit-interrupting means at a terminal of a line-section to be protected, comprising nrst, second, and third-Zone distance-responsive relaying-means for responding to line faults at different distances from the relaying terminal, directionally responsive relaying-means for responding when said faults are accompanied yby a current-direction into the protected line-section at the relaying terminal, an auxiliary relay, an electronic tube, means for utilizing a contact of the third-zone relay and the coil ci the auxiliary relay in series with each other for together effecting a control over the condition ci operation or non-operation of the electronic tube, and means for utilizing the operations cf directional relay, said rst and second-zone relays, said auxiliary relay, and said electronic tube, in the control of a plurality of control-circuits for causing line-sectionalizng circuit-interrupter operations,

lt'. Protective relaying equipment for controlling a line-sectionalizing circuit-interrupting means at a terminal of a line-section to be protected, comprising first, second, and third-zone distance-responsive relaying-means ior responding to line-faults at different distances from the relaying terminal, at least some oi said relaying-means directionally responding when said faults are accompanied by a current-direction into the protected line-section at the relaying terminal, an auxiliary relay, an oscillator-tube, means :for utilizing a contact of the third-zone relay and the coil of the auxiliary relay in series with each other for together quickly controlling the energization of the plate-cathode .circuit of the oscillator-tube, means for causing the cathode of the oscillator-tube to be biased with respect to the potentials controlled by said third-zone contact, and means for utilizing the operations of said first and second-zone relays, said auxiliary relay and said oscillator tube in the control of a plurality of control-circuits for -causing line-sectionalizing circuit-interrupter operations.

ll. Protective relaying equipment for controlling a line-sectionalizing circuit-interrupting means at a terminal of a line-section to be protected, comprising irst, second, and third-zone distance-responsive relaying-means for responding to line-faults at different distances from the relaying terminal, directionally responsive relaying-means for responding when said faults are accompanied by a current-direction into the protected line-section at the relaying terminal, an auxiliary relay, an oscillator-tube, means for utilizing a contact o1" the third-zone relay and the coil of the auxiliary relay in series with each other for together quickly controlling the energization of the plate-cathode circuit of the oscillator-tube, means for causing the cathode of the oscillatortube to be biased with respect to the potentials controlled by said third-zone contact, and means for utilizing the operations of said directional relay, said first and second-zone relays, said auxiliary relay, and said oscillator-tube, in the control of a plurality of control-circuits for causing linesectionalizing circuit-interrupter operations.

l2. Protective relaying equipment for controlling a line-sectionalizing circuit-interrupting means at a terminal of a line-section to be protected, comprising -rsty second, and third-zone distance-responsive relaying-means for responding to line-faults at different distances from the 'iii relaying terminal, at least one of said relaying-means directionally responding when said faults are accompanied by a current-direction into the protected line-section at the relaying terminal, an auxiliary relay, an electro-nic keyer including an oscillator-tube, a series dropping resistor for the oscillator-tube, a supply-circuit for the oscillator-tube, means for utilizing the series dropping resistor in a circuit between the anode of the oscillator-tube and the positive terminal of the supply-circuit, means for utilizing a contact of the third-zone relay and the coil of the auxiliary relay in series with each other in a circuit between the anode of the oscillator-tube and the negative terminal of the supply-circuit, means for causing the cathode of the oscillatortube to be biased with respect to the terminals ci said supply-circuit, and means for utilizing the operations of said rst and second-zone relays, said auxiliary relay and said electronic keyer in the control of a plurality of control-circuits for causing line-sectionalizing circuit-interrupter operations.

13. Protective relaying equipment for controlling e, line-sectionalizing circuit-interrupting means at a terminal of a line-section to be pro.- tected, comprising rst, second, and third-zone distance-responsive relaying-means for responding to line-faults at different distances from lie relaying terminal, directionally responsive relaying-means for responding when said faults are accompanied by a current-direction into the protected line-section at the relaying terminal, an auxiliary relay7 an electronic keyer including an oscillator-tube, a series dropping resistor for the oscillator-tube, a supply-circuit :for the oscillatortube, means for utilizing the series dropping resistor in a circuit between the anode of the oscillator-tube and the positive terminal of the supply-circuit, means for utilizing a contact of the third-zone relay and the coil of the auxiliary relay in series with each other in a circuit between the anode of the' oscillator-tube and the negative terminal ci the supply-circuit, means for causing .the cathode of the oscillator-tube tc oe with respect to the terminals oi said supplycircuit, and means for utilizing the operations of said directional relay, said rst and secondzone relays, said auxiliary relay, and said electronic keyer, in the control of a plurality of control-circuits for causing line-sectio-nalizing circuit-interrupter operations.

14. Protective relaying equipment for controlling a line-secticnalizing circuit-interrupting means at a terminal of a line-section to be protected, comprising rst, second, and third-zone distance-responsive relaying-means for responding to line-faults at dierent distances from the relaying terminal, at least some of said relayingmeans directionally responding when said faults are accompanied by a current-direction into the protected line-section at the relaying terminal, an auxiliary relay, carrier-current relaying-'1pparatus, an electronic keyer including an oscillater-tube, a series dropping resistor for the oscillator-tube, a supply-circuit for the oscillatortube, means for utilizing the series dropping resistor in a circuit between the anode of the oscillator-tube and the positive terminal of the supply-circuit, means for utilizing a Contact of the third-zone relay and the coil of the auxiliary relay in series with each other in a circuit between the anode of the oscillator-tube and the negative terminal of the supply-circuit, means for causing the cathode of the oscillator-tube to be biased with respect to the terminals of said supply-circuit, means for utilizing the electronic keyer in the ccntroi of the carrier-current transmission of the carrier-current relaying-apparatus, and means for utilizing the operations of said iirst and second-zone relays, said auxiliary relay and said carrier-current relaying apparatus in the control of a plurality of control-circuits for causing line-sectionalizing circuit-interrupter operations.

15, Protective relaying equipment for controlling a line-sectionalizing circuit-interrupting means at a terminal of a line-section to be protected, comprising rst, second, and third-zone distance-responsive relay-means for responding to line-faults at different distances from the relaying terminal, directionally responsive relayingmeans for responding when said faults are accompanied by a current-direction into the protected line-section at the relaying terminal, an auxiliary relay, carrier-current relaying-apparatus, an electronic keyer including an oscillatortube, a series dropping resistor for the oscillatortube, a supply-circuit for the oscillator-tube, means for utilizing the series dropping resistor in a circuit between the anode of the oscillator-tube and the positive terminal of the supply-circuit, means for utilizing a contact of the third-zone relay and the coil of the auxiliary relay in series With each other in a circuit between the anode of the oscillator-tube and the negative terminal of the supply-circuit, means for causing the cathode of the oscillator-tube to be biased with respect to the terminals of said supply-circuit, means for utilizing the electronic keyer in the control of the carrier-current transmission of the carrier-current relaying apparatus, and means for utilizing the operations of said directional relay, said rst and second-zone relays, said auxiliary relay, and said carrier-current relaying apparatus, in the control of a plurality of control-circuits for causing line-sectionalizing circuit-interrupter operations.

16. Protective relaying equipment for controlling a line-sectionalizing means at a terminal of a line-section to be protected comprising rst, second, and third-zone distance-responsive relaying-means for responding to line-faults at diiierent distances from the relaying terminal, at least some of said relayingi means directionally responding When said faults are accompanied by a current-direction into the protected line-section at the relaying terminal, an oscillator-tube, a supply-circuit for the oscillator-tube, a control-circuit serially including a i Contact of the third-zone relay and a resistor, connected across said supply-circuit, a connection-means for connecting an intermediate point of said control-circuit to the plate of the oscillator-tube, means for causing the cathode of the oscillator-tube to be biased with respect to the terminals of said supply circuit, and means for utilizing the operations oi said iirst and secondzone relays, and said oscillator-tube, in the control of a plurality of control-circuits for causing line-sectionalizing circuit-interrupter operations.

circuit-interrupting f 17. Protective relaying equipment for controlling a line-sectionalizing circuit-interrupting means at a terminal of a line-section to be protected comprising first, second, and third-zone distance-responsive relaying-means for responding to line-faults at different distances from the relaying terminal, directionally responsive relayingmeans for responding when said faults are accompanied by a current-direction into the protected line-section at the relaying terminal, an oscillator-tube, a supply-circuit for the oscillator-tube, a control-circuit serially including a contact of the third-zone relay and a resistor, connected across said supply-circuit, a connection-means for connecting an intermediate point of said controlcircuit to the plate of the oscillator-tube, means for causing the cathode of the oscillator-tube to be biased with respect to the terminals of said supply circuit, and means for utilizing the operations of said directional relay, said rst and second-zone relays, and said oscillator-tube, in the control of a plurality of control-circuits for causing line-sectionalizing circuit-interrupter operations.

18. Protective relaying equipment for controlling a line-sectionalizing circuit-interrupting means at a terminal of a line-section to be protected comprising rst, second, and third-zone distance-responsive relaying-means for responding to line-faults at dierent distances from the relaying terminal, directionally responsive relaying-means for responding when said faults are accompanied by a current-direction into the protected line-section at the relaying terminal, an auxiliary third-zone relay, an auxiliary directional relay, an oscillator-tube, a supply-circuit for the oscillator-tube, a control-circuit serially including a contact of the third-zone relay, the coil of the auxiliary third-zone relay, a contact of the auxiliary directional relay, and a resistor, connected across said supply-circuit, a connectionmeans for connecting an intermediate point of said control-circuit to the plate of the oscillatortube, means for causing the cathode of the oscillator-tube to be biased with respect to the terminals or said supply circuit, and means for utilizing the operations of said directional relay, said rst and second-zone relays, said auxiliary relay, and said oscillator-tube, in the control of a plurality of control-circuits for causing line-sectionalizing circuit-interrupter operations.

SHIRLEY L. GOLDSBOROUGH. HERBERT W. LENSNER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS liuniber Name Date 1,877,454 Goldsborough Sept. 13, 1932 1,934,662 Goldsborough Nov. 7, 1933 2,044,174 Lewis et al. L June 16, 1936 2,255,934 Lenehan et al. Sept. 16, 1941 

